Enhanced photocatalytic degradation of xylene by blackening TiO2 nanoparticles with high dispersion of CuO

Wenjun Zhou; Boxiong Shen; Fumei Wang; Xiao Zhang; Zhong Zhao; Meng Si; Shengqi Guo

doi:10.1016/j.jhazmat.2019.121642

Enhanced photocatalytic degradation of xylene by blackening TiO₂ nanoparticles with high dispersion of CuO

J Hazard Mater. 2020 Jun 5:391:121642. doi: 10.1016/j.jhazmat.2019.121642. Epub 2020 Feb 1.

Authors

Wenjun Zhou¹, Boxiong Shen², Fumei Wang¹, Xiao Zhang¹, Zhong Zhao¹, Meng Si¹, Shengqi Guo¹

Affiliations

¹ School of Energy and Environmental Engineering, Key Laboratory of Clean Energy Utilization and Pollutant Control in Tianjin, Hebei University of Technology, China.
² School of Energy and Environmental Engineering, Key Laboratory of Clean Energy Utilization and Pollutant Control in Tianjin, Hebei University of Technology, China. Electronic address: shenbx@nankai.edu.cn.

PMID: 32045798
DOI: 10.1016/j.jhazmat.2019.121642

Abstract

To enhance the photocatalytic activity of TiO₂, a new preparation method has been proposed to synthesize the catalysts by introducing Cu-MOF as a precursor and performing a blackening process via a mixture with NaBH₄ for TiO₂ nanoparticles (CuO-TiO₂(mb)). The results showed that the removal efficiency of xylene under ultraviolet and visible light over CuO-TiO₂(mb) was 3.45 times higher than that of the catalysts prepared by impregnation of CuO on the surfaces of TiO₂ (CuO-TiO₂(d)) and 12.12 times higher than that of pure TiO₂ nanoparticles. Analyses by the X-ray diffraction, scanning electron microscopy, and transmission electron microscopy indicated that the introduction of Cu-MOF as a precursor on the surface of the catalyst resulted in CuO-TiO₂(mb) presenting a lower grain size compared with TiO₂ nanoparticles and CuO-TiO₂(d). The results of X-ray photoelectron spectroscopy, diffuse reflectance spectrum and photoluminescence indicated that blackening process narrowed the bind gap width and shortened the band gap from 2.95 eV to 1.32 eV, introduced the coexistence of Ti⁴⁺, Ti³⁺, Cu²⁺ and Cu⁺ in CuO-TiO₂(mb) decreased the recombination rate of e^--h⁺, which greatly improved the light response of CuO-TiO₂(mb) under ultraviolet and visible light, resulting in the benefit to the photocatalytic reaction.

Keywords: Blackening process; CuO modification; Photocatalysis; Xylene removal.